WebGL: passing uniform arrays to shader

Question

Tried to do just like here: Pass array to shader And like here: Passing an array of vectors to a uniform

But still no luck. I think I do just like there but it doesn't work:

Here's my JavaScript code:

shaderProgram.lightsUniform = gl.getUniformLocation(shaderProgram, "lights"); // Getting location
gl.uniform1f(shaderProgram.lightsUniform, new Float32Array([3,1,2,3,4,5])); // Let's try to send some light (currently each light is one float) as array.

Vertex Shader Code:

uniform float lights[6]; // Declaration

...

vLight *= lights[0]; // Let's try to mutliply our light by the first array item. There should be 3.0.

Summary: I send an array to shader with non-zero-floats.

Result: totally black! I.e. lights[0] contains 0.0 but expected 3.0. If I try lights[1], lights[2] etc. they all give the same result!

Let's now try to pass just one float. I change

gl.uniform1f(shaderProgram.lightsUniform, new Float32Array([3,1,2,3,4,5])); 

to

gl.uniform1f(shaderProgram.lightsUniform, 3); // I want to send just float 3.0

Summary: instead of sending array I send just float 3.0.

Result: works! lights[0] contains 3.0 (but I sent just float, not an array).

What do I do wrong? How do I pass to shader array of uniforms?

Answer 1

Those answers all use the function uniform3fv. v as in vector.

So you should be using uniform1fv, not uniform1f for arrays of uniforms. In the future, please be more careful when reading answers. Or failing that, check your OpenGL errors before asking questions.

Answer 2

1: Make sure your if statement is within a function.

2: Make sure precision is set before declaring uniforms.

      #ifdef GL_FRAGMENT_PRECISION_HIGH
        precision highp float;
      #else
        precision mediump float;
      #endif
      precision mediump int;

3: Make sure comparison is of correct type:

This will FAIL:

uniform vec3 neon_whatever;
if(neon_whatever.x == 0){

};

This will FAIL:

uniform vec3 neon_whatever;
if(neon_whatever == 0.0){

};

This will WORK:

uniform vec3 neon_whatever;
if(neon_whatever.x == 0.0){

};